利用近红外光谱在不同光程下对山茶油中掺杂大豆油的掺伪量进行定量检测研究,着重分析光程对掺伪量检测精度的影响.将大豆油按一定质量分数掺入山茶油获取实验样本,掺伪质量分数范围为1%～50%.利用QualitySpec型光谱仪采集样本在不同光程(1,2,4,10 mm)下的透射光谱,通过对比不同建模方法、预处理方法及建模波段范围所建立的掺伪量定量预测模型,分析光程对掺伪量检测精度的影响.研究结果表明,光程由1 mm增加到4 mm时,掺伪量定量预测模型性能随着光程的增加而逐渐变好,检测精度逐步提高;光程由 4 mm增加到10 mm时,掺伪量定量预测模型性能变差,检测精度下降,4 mm为较优的光程.在1,2,4和10 mm下所建立的较优掺伪量定量预测模型的预测集决定系数(R2P)和预测均方根误差(RMSEP)分别为0.923,0.977,0.989,0.962和4.58%,2.54%,1.72%,3.20%。

In this research,near infrared spectroscopy was used to detect adulterated percent of camellia oil adulterated with soybean oil quantificationally at different optical lengths,and the effect of optical length on detection accuracy of adulterated percent was investigated.Soybean oil was put into camellia oil according to different mass fraction,the adulterated mass fraction was ranged from 1% to 50%.Transmission spectra of samples were acquired by a Quality Specspectrometer at different optical lengths(1,2,4,10 mm),and effect of optical length on detection accuracy of adulterated percent was analyzed by comparing quantitative prediction models that developed at different calibration methods,pretreatment methods and wavelength range.The results indicate that the performance of quantitative prediction model of adulterated percent is improved as the optical length is increasing from 1 to 4 mm,while the performance of quantitative prediction model of adulterated percent is deteriorated as the optical length is increasing from 4 to 10 mm.4 mm is a better optical length for camellia oil adulteration.The coefficients of determination of prediction(R2P) and root mean square error of prediction(RMSEP) in quantitative prediction models of adulterated percent for optical lengths of 1,2,4,10 mm are 0.923,0.977,0.989,0.962 and 4.58%,2.54%,1.72%,3.20%,respectively.